1. Technical Field
The present invention relates to an organic electroluminescence device, a process of producing an organic electroluminescence device, and an electronic apparatus.
2. Related Art
With diversification of information apparatuses, needs for flat displays that consume lower amounts of power and are reduced in weights have increased. As an example of such flat displays, organic electroluminescence devices (hereinafter, referred to as “organic EL devices”) having organic light-emitting layers are known.
The organic EL device includes a plurality of organic light-emitting elements (organic EL elements) having a configuration wherein an organic light-emitting layer (light-emitting layer) or a functional layer such as an electron injection layer is disposed between an anode and a cathode. Among these components, the cathode and the electron injection layer are made of materials having properties of easily releasing electrons and thereby react with moisture in the air and are readily deteriorated. The deterioration of these components forms a non-emission region called a dark spot. Therefore, in the organic EL device, a sealing structure for blocking moisture in the air from the organic light-emitting elements is important.
Recently, it has become possible to block the external atmosphere from the organic light-emitting elements by a thin sealing film having a thickness of several micrometers. By using such a sealing technology, a complete solid structure can be realized without providing a hollow structure for filling a gas or a liquid in the inside. The organic EL device having the solid structure makes it possible to significantly reduce the thickness and weight, and therefore it can be expected to make the organic EL device to have further high function and high quality.
In the above-described thin sealing film, infiltration of moisture from the external atmosphere is blocked using an inorganic compound layer that is transparent and has low moisture permeability. Unfortunately, such an inorganic compound layer has a high density, a high Young's modulus, and a high membrane stress and thereby has a disadvantage of being fragile to be easily broken. In addition, the periphery of the organic light-emitting elements covered with the sealing film has asperities due to, for example, pixel partition wall disposed between the light-emitting elements and wiring connected to the light-emitting elements, and therefore the inorganic compound layer particularly tends to be broken at these asperities. An increase in the thickness of the inorganic compound layer for preventing breakage thereof increases the residual stress when the layer is formed. This readily causes warpage and cracking and may rather decrease performance of the layer. Once the sealing film is broken, moisture sequentially infiltrates from the breakage portion, and thereby the light-emitting elements are continuously deteriorated. Then, a dark spot is not only generated at the breakage portion of the sealing film but also grows in all directions with respect to the breakage portion as the center. Therefore, the non-emission region broadens to the circumference thereof, resulting in a significant reduction in product lifetime.
Accordingly, proposed is a configuration where a resin layer for planarizing the asperities and absorbing thermal stress and an inorganic compound layer preventing moisture penetration are stacked (for example, see JP-A-10-312883 and JA-A-2000-223264). In addition, a technology for suppressing breakage, realizing high coverage, and achieving satisfactory sealing by laminating inorganic compound layers made of different materials or having different densities and covering the light-emitting elements with such a laminated structure is proposed (for example, see JP-A-2007-184251 and JA-A-2003-282237).
However, in the case that the inorganic compound layer is laminated on the resin layer, the resin layer is expanded or contracted due to, for example, a change in temperature when the inorganic compound layer is formed on the resin layer, and the inorganic compound layer on an end of the resin layer cannot follow the expansion or contraction and may have cracking. In the case not including the resin layer, it is difficult to planarize the asperities at the periphery of the light-emitting elements, and thereby asperities, which readily cause breakage of the inorganic compound layer, remain, resulting in low reliability of the produced organic EL device.